1. Field of the Invention
This invention relates to an adapter device for connecting a unit of peripheral equipment, such as an electronic camera, to an external apparatus.
2. Description of the Related Art
In the field of electronic cameras in which image information is obtained by means of an image sensor, the recent advancement of digital technology and large-capacity storage technology has made it practicable for the electronic cameras to handle moving-image information or still-image information as digital signals. The digitized image information can be inputted or outputted directly into or out of various system units such as a printer, a host computer, etc.
In cases where the digital image information is to be exchanged between the electronic camera and a TV monitor or a computer, it is necessary to use many signal terminals, unlike in the case of the NTSC video signal system or the like. For this purpose, a connector having an array of terminals is normally employed as an external output terminal, like a connector for a personal computer. However, for the convenience of mounting and demounting and also in respect of reliability, adapter devices having such connectors for exclusive use in the electronic cameras have been developed in various shapes suited to camera bodies.
In general, a camera of the above-stated kind is used repeatedly in two conditions, i.e., a condition in which the camera alone is used at the time of a shooting action and a condition in which the camera is connected to an external apparatus at the time of inputting and outputting of information. With the camera used in this manner, when a recorded image is reproduced on a TV monitor or is inputted to a computer, the following methods are employed.
(1) A recording medium is taken out from the camera and is then mounted on a recording and reproducing apparatus which is either connected to the TV monitor or built in or connected to the computer. Images and sounds are then reproduced by the recording and reproducing apparatus.
(2) The camera is connected through a cable to the TV monitor or the computer so as to input and output images, sounds and control signals directly into or from the TV monitor or the computer.
(3) A camera mounting/connecting device which is constantly connected to the TV monitor or the computer and which is capable of setting the camera thereon to readily connect the camera thereto is used instead of the cable.
The above-stated known system connection methods, however, have presented various problems. For example, the method (1) requires use of a recording and reproducing apparatus. The use of the recording and reproducing apparatus not only causes the size of the system to increase but also makes it impossible to reproduce the record if the recording medium is not of the same kind. Besides, the method (1) does not apply to a camera which is arranged to record signals on a built-in memory and which does not permit use of an interchangeable recording medium.
The method (2) requires a manual action for connection of the cable, which is troublesome particularly in the case of a computer having a connector on the rear side thereof. The trouble may be avoidable by leaving the cable in a connected state. However, the cable connection might come off a desk or a stand to cause some inconvenience. Besides, with the camera connected to the cable, the camera tends to be pulled and caused to drop off the desk by the weight of the cable and thus might be damaged.
The method (3), on the other hand, necessitates some additional space for setting the camera mounting/connecting device on a desk or a stand.
FIGS. 9(a) to 9(c) are appearance views of a proposed prototype of adapter device as viewed on its three different sides. FIGS. 10(a) and 10(b) are side views showing the internal arrangement of the adapter device shown in FIGS. 9(a) to 9(c).
Referring to FIGS. 9(a) to 9(c), with a camera 200 mounted on a body 501 of the adapter device in a predetermined position 501a, when an operation lever 502 is moved in a mounting direction, a lock member 504 which is provided for securing the camera 200 to the adapter device body 501 is first inserted into a lock hole 200a provided in the camera 200. Then, at the same time, a protection cover 505 is opened. When the operation lever 502 is moved further in the mounting direction, a cam plate 506 disposed in the inside 503 of the adapter device body 501 slides rightward as viewed on FIG. 10(a). The sliding motion of the cam plate 506 causes a lift arm 508 to swing counterclockwise on a shaft 508a by pushing a roller 508b upward. A slot 508c is provided in the lift arm 508. A connector 510 is provided with a shaft 510a which is inserted into the slot 508c. The connector 510 is moved upward according to the counterclockwise swing of the lift arm 508 and then inserted into a terminal 200c of the camera 200, as shown in FIG. 10(b).
The amount of ascent of the connector 510 in relation to the amount of movement of the operation lever 502 varies with the angle of inclination of the cam lift of the cam plate 506. The connector 510 quickly ascends if the angle of inclination of the cam lift is arranged to be steep, while the connector 510 slowly ascends if the angle of inclination of the cam lift is arranged to be moderate. In an "initial position", the connector 510 is buried within the adapter device body 501, as shown in FIG. 10(a). From the initial position, the connector 510 is swiftly moved upward with no load up to a "coupling start position" where the connector 510 begins to be coupled with the terminal 200c of the camera 200. After that, the connector 510 is preferably caused to slowly ascend up to a "coupling completed position", as some amount of force is required for inserting the connector 510 into the terminal 200c.
In view of the above, as shown in FIG. 11, the angle of inclination of the cam lift of the cam plate 506 is arranged to be divided into two parts, i.e., a first cam lift part 506a which has a steep angle of inclination and a second cam lift part 506b which has a moderate angle of inclination. Thus, by effectively utilizing a limited operation range of the operation lever 502, it is possible to give the connector 510 a desirable operating condition.
However, the above prototype of adapter device has presented a shortcoming in the following point. That is, the adapter device has become incapable of fully coping with an increase in the inserting force for the connector 510. While, for peripheral equipment such as the digital electronic camera of the above kind, as mentioned above, it is necessary to provide a plurality of signal terminals, the number of signal terminals has increased for the purpose of improving functions of the peripheral equipment and the contact pressure of the signal terminals also has increased for the purpose of ensuring the reliability of terminal conduction. As a result, it has become necessary to increase the inserting force for the connector 510.
Roughly speaking, the increase of the inserting force for the connector 510 calls for improvement in the following three points.
(i) A first point lies in the insufficient strength of a lock mechanism part. The lock member 504 shown in FIGS. 9(a) to 9(c) is provided for preventing the camera 200 from buoying up when the connector 510 is inserted into the terminal 200c of the camera 200. However, the increase of the inserting force for the connector 510 naturally results in a larger force on the lock member 504. Specifically, the connector 510 has terminals widely aligned in the direction of a line X--X shown in FIG. 9(a). Therefore, the conventional arrangement of providing the lock member only at one position has caused the terminals to be in a poorly balanced state and thus has been hardly sufficient.
(ii) A second point lies in the possibility of having the connector 510 inadequately inserted. With the inserting force for the connector 510 increased, the deviation of the connector position taking place on the side of the camera 200 and the flexure or eccentricity due to play taking place at each mechanism part within the adapter device body 501 increase to cause a decrease in actual stroke of the connector 501. Under such a condition, the actual inserted position of the connector 501 fails to reach the "coupling completed position", thereby lowering the reliability of the conducting state of the signal terminals.
(iii) A third point lies in the flexure in pulling out the connector 510. The force of pulling out the connector 510 is about equal to the force of inserting the connector 510. The above-stated eccentricity due to play or flexure which takes place at the time of inserting the connector 510 naturally takes place in an about the same amount in the reverse direction in pulling out the connector 510. Then, the actual stroke of the connector 510 in pulling out the connector 510 also decreases. Under such a condition, the connector 510 might fail to be brought back to the "coupling start position" and thus might be left in a state of being incompletely pulled out.
Therefore, in the case of a design where the cam lift changes at the "coupling start position" from one angle of inclination over to another as shown in FIG. 11, at the time of pulling out the connector 510, the lift arm 508 comes to the first cam lift part 506a of the steep angle of inclination before the connector 510 is completely pulled out. Then, the operating force on the operation lever 502 suddenly comes to have a heavy load halfway in pulling out the connector 510. This trouble might be avoidable by setting the cam lift change-over point at a point located before the "coupling start position". Such a solution, however, necessitates the second cam lift part 506b to be arranged to have a steeper cam lift angle of inclination. Then, the steeper angle of inclination imposes a heavier load on the operating force on the operation lever 502 over the whole range of stroke both in inserting and pulling out the connector 510.